Metal-coated material obtained by coating metal over the surface of the base material is useful, because the metal gives metal-derived properties such as hardness, electroconductivity, and solvent resistance to the surface of the base material. Therefore, many studies have been made about various materials.
By those studies, various methods to coat metal over the surface of particulate materials are proposed. For example, Non-Patent Document 1 discloses a method to coat gold to SiO2 beads of which surface is modified with silane coupling agent having amino terminals. Non-Patent Document 2 discloses a method by making gold nanoparticles adsorbed on a polystyrene latex to which polyelectrolyte is adsorbed so as to realize reductive extraction of gold by use of the adsorbed polystyrene latex as the foothold. Further, Non-Patent Document 3 discloses a method to coat silver to SiO2 beads by adding silver salt to SiO2 beads on which Sn2+ is adsorbed.    Non-Patent Document 1: Chemical Physics Letters, 288 (1998), pp. 243-247    Non-Patent Document 2: Advanced Materials, 13 (2001), pp. 1090-1094    Non-Patent Document 3: Chemistry of Materials, 13 (2001), p. 1630